Livestock production requires careful application of both science and animal husbandry practices in order to obtain the meat quality characteristics desired by the consumer. Feed costs are a livestock producer's most significant cost and it is desirable to manage expected carcass characteristics, include supplements in the diet that improve those characteristics, improve the health of the animal, and minimize the costs of the feed and other costs associated with livestock production.
Saturated fatty acids (SFA) tend to positively influence fat quality by increasing firmness when included in the diet; UFA tend to negatively affect fat by causing it to have a softer composition which translates to higher levels of oxidation, and increased slicing and processing difficulties. Fat firmness can be monitored by determining the fatty acid profile and calculating an iodine value (IV). Acceptable IV scores vary depending on the processor; however, as an example, at the present time, an IV score over 73 for swine frequently indicates soft fat and a less desirable carcass.
In recent years, ethanol production in the Midwest has become commonplace. The basic process includes cooking corn into mash, adding yeast and fermenting the mash, distilling off the ethanol, and thereafter separating the solids remaining from the liquid. Some of the liquid can be used as backset in the process, oil might be separated from the liquid, and additional solids might be separated from the liquid. The remaining and/or separated solids are called wet distiller's grains (WDG) and typically include around 70% moisture. Although high in protein and well suited for use as an animal feed supplement, the shelf life of WDG is very short. Therefore, WDG are often dried to around 10% moisture, creating a feed ingredient called dried distillers grains or dried distillers grains with solubles (both referred to herein as DDGS) with a much longer shelf life.
The interest in uses for ethanol process byproducts has grown since their more abundant availability due to the ethanol industry's growth since 2000. The DDGS is the result of removal of corn starch which results in concentration of non starch components of corn approximately three fold in the DDGS. DDGS includes nutritional and economic values that make them attractive for use as animal feeds or feed additives. Specifically, DDGS has about 9-10% fat (about double that of whole corn), around 8-9% fiber (approximately four times that of whole corn), about 25-30% crude protein (which is about 3½ times that of whole corn), around 0.6-0.9% lysine (about triple that of whole corn) without significant loss of calcium or phosphorus. However, DDGS also typically contains about 10% corn oil, which is high in UFA, so despite DDGS significantly lowering feed costs at higher inclusion rates, feeding only low levels of DDGS was recommended due to the negative carcass impact. For swine, DDGS was recommended at 10% of the diet for grow finish hogs, with a maximum of 20%. (Plain, Ron, “Feeding Distiller Grains to Hogs” Factsheet, Livestock Marketing Information Center, State Extension Services, University of Missouri-Columbia, Fall 2008). Iowa State University Extension recommended up to 20% DDGS in nursery, grow-finish, and lactating sow diets, and up to 40% for gestating sows; this paper further reported that diet levels above 20% DDGS can produce a softer, oilier fat in pigs. (Mark Honeyman, Peter Lammers, “Feeding Bioenergy Coproducts to Swine”, Iowa State University Extension, IPIC 11a May 2007). Feeding DDGS can also reduce carcass yield in swine production. DDGS recommended supplementation rates in diets for cattle are also varied according to the growth stage or end purpose of the animal. Poultry diets can also be supplemented with DDGS.
Other than the effect on carcass yield and carcass fat mentioned herein, feeding DDGS does not change quality or grades of carcasses. Further, feed cost of gain will typically be reduced if the cost of DDGS is not at a level that is much greater than the cost of corn grain on a dry basis. In short, DDGS has high protein and fat content and can be included into a number of livestock diets.
The fat component of DDGS is corn oil and is known to affect carcass fat softness. (BioEnergy “The Influence of Dried Distillers' Grains on Carcass Fat in Swine” Mickey A. Latour, A. P. Schinckel, Purdue University, Purdue Extension ID-345-W 8/07). As a basic premise, pig body composition is affected by the feed's fat content. This is because pigs can directly deposit dietary fat into their fat depots. The transfer from diet to body fat is well characterized in grow-finish pigs. Id. Cattle and poultry do not share this mechanism of fat deposition, however, adding certain fat or increasing the level of fat in the diet does affect the hardness of the fat of poultry and bovine carcasses as well.
The addition of DDGS increases the level of UFA in the diet. In short, the acceptable level of DDGS in the diet is limited by its negative result of producing softer carcass fat and undesirable IV scores. There are other sources of UFA used in swine, cattle and/or poultry diets, including but not limited to, dried bakery product, corn oil, soybean oil, poultry fat and yellow grease, that also contribute to soft carcass fat. The present invention comprises a method of feeding that allows higher inclusion of DDGS and other sources of UFA while managing the softness of carcass fat and IV scores.
The economic advantages offered by substituting DDGS (or other less expensive feed materials that have increased fat content) for other more traditional feed components can be significant. Swine producers, poultry producers and cattle producers have continued to use DDGS as a feed supplement but do so at levels chosen to manage or avoid the negative effects that feeding more DDGS would be expected to cause. In other words, the full economic and nutritional benefits of DDGS supplementation are not being fully realized.
Ractopamine is a feed additive used to improve carcass leanness and growth rate in swine and cattle. Pharmacologically, it is a beta-adrenergic agonist that functions to increase protein synthesis resulting in increased muscle fiber size. Ractopamine is typically fed to growing swine during the last 3-5 weeks prior to slaughter to increase carcass lean and growth rate. Ractopamine is very commonly used as a feed additive in U.S. swine diets. It is estimated that over 70% of the swine produced in the U.S. have been fed ractopamine (personal communication with Elanco, makers of ractopamine). Ractopamine is used for similar purpose and with similar effects with cattle. However, ractopamine also has unfortunate negative impacts on meat quality. Carr et. al., (2005) observed that feeding ractopamine at 10 or 20 ppm for 25 to 41 days pre-slaughter resulted in poorer color scores, reduced tenderness and reduced flavor scores. Stoller et. al., (2003) reported that feeding ractopamine at 10 ppm for 28 days resulted in reduced color score, reduced tenderness score, increased chewiness score and increased Instron force of loin muscle. Aalhus, et. al., (1990) found that feeding ractopamine at 10 ppm for 35 days prior to slaughter increased sheer force of loin muscle and reduced hardness of fat samples taken from the loin.
Overall, desirable carcass characteristics can be measured and relate to lean color, marbling, lean firmness, water holding capacity, muscling, fatness, and softness of fat. What was needed was a method of feeding animals that would allow the maximum nutritional advantage of employing DDGS as a feed ingredient, would allow realization of the maximum economic advantage of employing DDGS, and would counter the negative effects otherwise expected from feeding relatively high levels of DDGS or other feed ingredients high in UFA. Further, what was needed was a method for countering the negative effects on carcass characteristics associated with the use of ractopamine. Finally, what was needed was a method for improving carcass characteristics expected from standard diets.
It is a first objective of the present invention to provide a method for feeding an animal a feed containing high levels of UFA without decreasing the melting point of the carcass fat or without the expected decrease in melting point of the carcass fat.
A second objective of the method is to provide a method for feeding livestock and poultry higher levels of UFA without increasing the IV score.
A third objective of the method is to provide a method for feeding meat-bearing livestock that improves meat quality (e.g., fat hardness, cooking loss, and belly thickness) while not adversely impacting the productivity of the animal (e.g., growth rate, feed efficiency) either when including DDGS or other supplements containing UFA at levels above the generally accepted levels, or when the UFA levels have not been increased.
A fourth objective of the method of the present invention is to reduce costs of animal feed by supplementing DDGS or other supplements with UFA, and decrease the IV score otherwise expected for UFA supplemented diets. One of the objectives is to increase the fat firmness over that which would have otherwise been expected from a diet supplemented with more than 20% DDGS in the early swine growth phase or more than 0% DDGS in the late swine growth phase.
A fifth objective of the method of the present invention is to reduce the negative effects otherwise expected when swine or cattle feed is supplemented with ractopamine.
A sixth objective of the method of the present invention is to improve the carcass characteristics of swine or cattle or poultry fed standard diets without the addition of ractopamine and without higher than normal levels of UFA.